A blanking device for multi-beams includes a substrate, a dielectric film formed on the substrate, plural first electrodes, at positions each exposed in a corresponding opening, to be applied with a first deflection potential, plural second electrodes, at positions each opposite to a corresponding first electrode with respect to the corresponding opening, to be applied with a second deflection potential, including a ground potential, for deflecting a corresponding beam of the multi-beams by a difference between the first and second deflection potentials, and a conductive film arranged in, other than plural first regions on the dielectric film each along a corresponding first electrode and being shaded by each first electrode in a case of being viewed from a position where a corresponding beam passes through a corresponding opening, a second region on the dielectric film, wherein insulation is provided between the plural first and second electrodes.